Name:	amch_ContractWithCustomerLiabilityForeignCurrencyTranslationAdjustment
Namespace Prefix:	amch_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of revenue reclassed that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

No definition available.

Name:	amch_ContractWithCustomerLiabilityRevenueReclassed
Namespace Prefix:	amch_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Represents the cash received in advance on various revenue streams.

No definition available.

Name:	amch_ContractsWithCustomersCashReceivedInAdvance
Namespace Prefix:	amch_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Represents deferred revenue associated with customer contracts.

No definition available.

Name:	amch_ContractsWithCustomersDeferredRevenue
Namespace Prefix:	amch_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

Name:	us-gaap_ChangeInContractWithCustomerLiabilityAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-8

Name:	us-gaap_ContractWithCustomerLiabilityRevenueRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Name:	amch_EquityMethodInvestmentActivityByClassificationAxis=amch_ExhibitorServicesAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	srt_ProductOrServiceAxis=us-gaap_AdmissionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	srt_ProductOrServiceAxis=us-gaap_FoodAndBeverageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: